Natural Wool Fibers Research Articles

On a correlation between the surface chemistry and the felting behavior of wool

AbstractThe felting behavior of wool fibers is found to be correlated with their flocculation properties. The interaction between the fibers is suggested as the common factor responsible for this correlation. It is observed that in a felting medium there is attraction between natural wool fibers. Such attraction is observed to be greatly diminished, or absent, after the wool has been shrinkproffed by any one of several chemical modification treatments. Hydrophobic attraction and electrostatic repulsion are proposed as significant components of the interaction between fibers in aqueous media. These components are linked to the surface chemistry of natural and chemically modified wool. It is proposed that the hydrophobic nature of the fiber surface promotes the felting shrinkage of natural wool fabrics, that shrink‐resist chemical treatments of wool top make the fiber surface more hydrophilic and may increase the electrostatic repulsion between fibers, and that the influence of surfactants on felting depends on the adsorption energy of the surfactant at the fiber surface. These ideas are presented as a guide for the development of further shrink‐resist chemical modifications of wool.

Anechoic chamber of novel design

Anechoic rooms are widely used in industrial testing and research on acoustic transducers and materials. The paper describes a chamber, designed and built at the University of Bradford for the dual purpose of research and teaching. The chamber designed was of necessity of small inside dimensions, and this fact dictated that the lining material had to be of high efficiency in order to leave the maximum usable internal volume. The acoustic properties of fibrous absorbers are discussed and a description of the methods used to classify fibrous material is given. The results of tests on several fibrous absorbers are presented, and the development of a highly efficient exponentially graded density configuration, using natural wool fibres or their equivalent, is described. The methods adopted in the Bradford University chamber to incorporate this favourable lining method are illustrated. The authors conclude by showing that the chamber, built as described, provides a highly satisfactory and economical solution to the problem.